1. Field of the Invention
The present invention relates generally to a method of recycling waste plastic materials, and more particularly to a method of recycling waste plastic foam materials including polyurethane foam materials and un-polyurethane foam materials.
2. Description of the Related Art
It is well known that use of polyurethane foam intermixed with un-polyurethane foam materials, such as nylon, polyester, cellulose films, glass fibers, and even natural fiber layers, as a daily article, for example, vehicle seats or shoe pads, has been increasing dramatically; and with this increase, there has developed a serious problem in disposing of waste foam materials.
In prior art, a method introduced to dispose foam waste was to take polyurethane foam, only the foam, from foam waste materials and grind it into a powder, and then mix such powder with a foamable polyurethane resin to produce a useful polyurethane foam material.
The drawback of the method mentioned above is that it is very difficult and not cost effective to separate only polyurethane foam from foam waste materials since they include so many distinct materials.